What does lockdown mean for electricity in Great Britain?

Coronavirus is having a significant impact on society. People are staying at home, and shops, businesses and industry are closed.

Our electricity control room experts Rob Rome and Jean Hamman explain the effect this is having on our electricity network, and why expert operation of the system is needed whatever the level of demand.

You might think people staying at home and using more electricity would mean an increased overall demand across the country, but that’s not the case. Electricity demand is actually significantly lower than usual, due to a decrease in energy use from large industrial consumers.

For many the assumption will be that lower demand makes it easier for us to do our job, with less power needed overall and therefore less stress on the system. In fact, as system operator, it’s just as important for us to manage lower demand for electricity as it is to manage the peaks – it's a different set of challenges that we plan for and are used to dealing with.

How much has demand dropped by?

The team has been analysing how electricity demand is changing since the nation started getting to grips with its new and unfamiliar daily routines.

The first graph below plots what we would consider a normal demand curve (the blue line) for a Monday at this time of year against demand seen by our control room yesterday (the red line), a week after restrictions were imposed on our movements. A normal day sees demand rise in the morning as we all get up and prepare for work or school at roughly the same time, before plateauing throughout the day. It’ll then peak early evening as we all get home, put the heating on and cook.

As you can see in the graph, daily demand in our current situation is following largely the same profile to date – but is reduced by around 10% overall, largely owing to those big industrial consumers using less power. One interesting trend we’ve seen is a slightly later morning peak than usual – a change we’d suggest might be because the times people are rising are a little later and more spread out (with fewer travelling to work and school).

The following graph shows percentage changes in demand at different periods of the day relative to the pre-pandemic demand levels (the black line indicates when lockdown measures were introduced).

The biggest change – supporting the trend we spotted above – is in morning demand (reductions of almost 18%), with reduced impact at the weekend when many of us might normally have been at home anyway.

We might start to see longer periods of low demand (days rather than hours) and we are testing all of this in advance. We are also ensuring that we can deploy all our tools when our National Control and wider industry may be at reduced/minimum staffing levels.

Operating the power system involves solving five engineering challenges (thermal, voltage, stability, frequency, restoration). We take real time action informed by detailed analysis and power system studies months and even years in advance.

We are working with network owners to configure the network to help alleviate voltage and thermal issues, while also allowing vital network maintenance and construction work continue. And we are ensuring that the generation fleet connecting to the power system allows us to solve the engineering challenges.